[gimp] libgimpwidgets: GimpSpinScale header was not listed.

[Jehan <jehanp src gnome org>]

commit 78fceca3535ac45ea4aae8ebbb79b068b50e4dfc
Author: Jehan <jehan girinstud io>
Date:   Sat Apr 9 18:35:15 2022 +0200

    libgimpwidgets: GimpSpinScale header was not listed.

 libgimpwidgets/meson.build | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/libgimpwidgets/meson.build b/libgimpwidgets/meson.build
index e4fa9f01ca..e047c2b42a 100644
--- a/libgimpwidgets/meson.build
+++ b/libgimpwidgets/meson.build
@@ -153,6 +153,7 @@ libgimpwidgets_headers_introspectable = files(
   'gimpscrolledpreview.h',
   'gimpsizeentry.h',
   'gimpspinbutton.h',
+  'gimpspinscale.h',
   'gimpstringcombobox.h',
   'gimpunitcombobox.h',
   'gimpunitstore.h',